The project proposed here will examine primary care physicians' involvement in cancer prevention and detection in a prepaid, managed care setting. Blue Cross Blue Shield of Massachusetts and Berkshire Health Plan (a Blue Cross Blue Shield Independent Practice Association (IPA) will work together to design, implement and evaluate and educational intervention intended to encourage cancer prevention and detection practices. The detection practices will include colorectal cancer screening through digital rectal exams, stool guaiac tests and proctoscopic exams and breast screening by mammography. Prevention activities will focus on physicians' involvement in smoking cessation. The study will involve a physician needs assessment, conducted through a questionnaire survey of Berkshire primary care physicians; documentation of existing cancer screening practices through a medical record review to determine rates of mammagraphies, sigmoidoscopies, stool guaiac tests, etc.; an educational program developed on the basis of identified needs and recommendations of local cancer education authorities; and a follow up evaluation of changes in practice behavior. The units of analysis will include all primary care practitioners in the Berkshire Health Plan, divided into experimental and control groups. Both groups will be part of the initial needs assessment/cancer screening practice pattern review. Only the experimental group will then receive the intervention. The cancer screening practices of both groups will be reevaluated during the posttest, using ANCOVA techniques. This study will enable us to describe the characteristics and needs of IPA physicians as a whole, guide the development of educational interventions at other sites, and make generalizations about the effect of the intervention on IPA physicians' cancer prevention practice patterns.